Russian opposition leader Aleksei Navalny says he has undergone surgery in Barcelona to repair his right eye, which was damaged last month when an assailant tossed a green antiseptic known as "zelyonka" in his face.

Navalny's post on Instagram on May 9 was his first public confirmation that he had left Russia for medical treatment amid mixed messages from officials about whether he is allowed to travel abroad.

Navalny, who has been convicted three times in financial-crimes trials that he calls Kremlin-orchestrated retribution for his activism, said on May 4 that he had obtained a passport for the first time after five years of trying.

His lawyer later said that corrections officials had warned that Navalny should "not dare to even think about" leaving Russia due to the suspended sentence he is serving out. A Moscow court spokesman later said his conviction did not directly ban him from traveling abroad.

The April 27 attack against Navalny was the latest in a series of zelyonka dousings targeting Kremlin critics in Russia.

Moscow police have launched an investigation, and members of a radical pro-Kremlin group Navalny accused of the attack say they have been contacted by investigators. The group, known as SERB, has denied involvement.

Navalny said earlier that his doctor believes the antiseptic was mixed with another substance that resulted in a chemical burn to his right eye.

He said in his May 9 Instagram post that his vision in the eye was still considerably impaired after surgery the previous day, and that it could take several months for it to be restored.

Opposition groups say the authorities have fostered an atmosphere of impunity that encourages such attacks on Kremlin critics.

With reporting by RIA Novosti

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